Patch merged into coreboot/master: rockchip/rk3399: sdram: correct controller vref setting

the following patch was just integrated into master:
commit df5ead9d2d01a03c4c3b00a1cb95c4e4b373bf1a
Author: Lin Huang 
Date:   Thu Jul 7 19:29:55 2016 +0800

rockchip/rk3399: sdram: correct controller vref setting

When enabling the controller ODT, the controller vref needs to
    correspond with the ODT value and DQ drive strength.

BRANCH=none
    BUG=chrome-os-partner:54871
    TEST=run "stressapptest -M 1024 -s 1000" on kevin board and pass

Original-Commit-Id: a7251c72b87d9f149b68d086c3252f1c668e0e80
    Original-Change-Id: I7e54b3473f68a382208a0fb0b0600552fe6390ad
    Original-Signed-off-by: Lin Huang 
    Original-Reviewed-on: https://chromium-review.googlesource.com/358762
    Original-Commit-Ready: Dan Shi 
    Original-Tested-by: Caesar Wang 
    Original-Reviewed-by: Julius Werner

Squashed with:

rockchip/rk3399: Halt if we get an invalid odt or drv value

When we were pushing the updated sdram.c to coreboot.org, the compiler
    there found that we were not initializing vref_value_dq in all code
    possible code paths.

This patch updates those code paths to halt the system.

Branch=none
    Bug=none
    Test=Built with coreboot.org toolchain and verified that the compile
    errors were gone.

Change-Id: I0ad4207dc976236d64b6cdda58d10bcfbe1fde11
    Signed-off-by: Martin Roth 
    Reviewed-on: https://chromium-review.googlesource.com/362726
    Reviewed-by: Julius Werner

Change-Id: I22a0cef6f12d9aae2ea4dcb99e7ebdd788f2cdd1
    Signed-off-by: Martin Roth 
    Reviewed-on: https://review.coreboot.org/15812
    Tested-by: build bot (Jenkins)
    Reviewed-by: Paul Menzel 
    Reviewed-by: Julius Werner

See https://review.coreboot.org/15812 for details.

-gerrit